寬頻表面聲波元件於陣列式光感測器之應用

Application of Slanted Finger Interdigital Transducer SAW Devices to Ultraviolet Array Photodetectors

余志明(Jhih-Ming Yu)

指導教授 ： 馬劍清

國立臺灣大學/工學院/機械工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01867

摘要

表面聲波元件（SAW）為一種廣泛應用的元件，如運用在濾波器、共振器、震盪器、感測器等，對現代生活帶來許多的便利性，而SAW會被廣為運用的幾個主因為體積小且為被動元件與可利用微機電製程大量製造等的優點。而為了提升元件的效應，必須使用高係數的壓電材料或是複合材料，也耦合了更多其他的效應在其中，如光電效應、熱電耦效應等，因此研究這些效應對表面聲波元件的影響就相當的重要。
在本文中，我們利用氧化鋅的光電特性與表面聲波元件間產生聲電耦合效應，藉此來製作光感測器，由於鈮酸鋰的表面波波速與機電耦合係數較高，可製作出高靈敏度的紫外光感測器，光波長感測範圍介於 之間，且可量測至 等級的微弱光源，由於單一線寬的表面聲波元件無法製作陣列化的光感測器，因此在本文中，我們利用斜指叉電極的特性，將光感測器製作為陣列化的量測元件，探討陣列化的感測元件在各種參數的變化下對表面聲波元件的影響，並成功的利用陣列化光感測器進行光強量測，並探討陣列化感測器的特性與量測結果比較。

關鍵字

寬頻 ； 表面聲波元件 ； 氧化鋅 ； 陣列 ； 光感測器 ； 紫外光

並列摘要

In recent years, surface acoustic wave (SAW) devices are commonly used as filters, resonators, sensors, etc.. SAW devices offer many attractive advantages, for example, they are passive and small by MEMS fabrication. They are highly sensitive and output signal has the form of RF signal allowing the combination with the wireless sensor. Sometimes, we must use piezoelectric materials with high coupling coefficients or layered structures in order to have better performance. Other interactions arise in SAW devices, such as temperature, and acoustoelectric effect. In this paper, we analyze the influence of UV light effect on the frequency characteristics of SAW devices, and these devices are used as a photodetector.
In general, velocity and attenuation of SAW devices are affected by acoustoelectric interations and/or mass loading effect. In this research, the interactions of acoustoelectric effect with piezoelectric fields is investigated. The substrate used in the SAW device is lithium niobate (LiNbO3) crystal which has high acoustic velocity and large electromechanical coupling coefficient, so that the SAW device used as the photodetector is sensitive to the intensity of UV light. The wavelength of UV light is between and , and a intensity in the order of is easily detected from the SAW devices. The photodetector is designed as the array photo sensors in SFIT SAW devices. The array sensors are used to analyze the distribution of the UV light field and the characteristics of sensors are discussed.

並列關鍵字

SFIT ； SAW ； ZnO ； Array ； sensor ； photodetector ； UV

參考文獻

Abbott B.P., Hartmann C.S. and Malocha D.C., “A Coupling-of-Modes Analysis of Chirped Transducers Containing Reflective Electrode Geometries,” IEEE Ultrason. Symp., 1989,pp. 129-134.

Campbell J. J. and Jones W. R., “A method for estimation optical crystal cuts and propagation directions for excitation of piezoelectric surface waves,”IEEE Trans. Son. Ultrason., Vol.15,1968,pp.209.

Campbell, C. K., Ye, Y. and Sferrazza PaPa, J. J., “Wide-Band Linear Phase SAW Filter Design Using Slanted Transducer Fingers,” IEEE Transactions on Sonics and Ultrasonics, Vol. SU-29 ,1982,pp. 224~228.

Ciplys D.,a),b) Rimeika R.,a) Shur M. S.,c) and Rumyantsev S., “Visible–blind photoresponse of GaN-based surface acoustic wave oscillator,” Appl. Phys. Lett., Vol.80, 2002.

Daniel, M. R. and de Klerk, J., “Acoustic Radiation Measurements and Calculations for Three Surface Wave Filter Designs,” Proc. IEEE Ultra. Symposium,1973,pp. 449~455.